What Is It?

What Is It? | Facts in Depth | For the Professional Diagnostician

Cucurbit Diseases | Bacterial Wilt

Bacterial Wilt


  • Individual leaves suddenly wilt and eventually shrivel
  • Early in the disease, leaves may “droop” during the heat of day but revert to normal in the evening or under cooler conditions
  • Leaves are darker green around the infected area
  • Xylem vessels inside the stem collapse and are discolored
  • Entire plant turns to a dull green color, collapses, and eventually dies

Bacterial wilt-pumpkin_50Quality Bacterial wilt-zucchini 2_50Quality BactWiltMelon-2_50Quality

(Left: Pumpkin; Middle: Zucchini; Right: Melon)

Favorable Environmental Conditions

  • Temperature and humidity do not influence the progress of the disease but may effect the expression of symptoms – early wilting is more prominent when plants are under heat or moisture stress
  • Conditions that would aid in the over-wintering, feeding, and reproduction of the vector – cold winters with low or no snow cover are unfavorable for beetle survival

Often Confused With

  • Squash vine borer damage
  • Fusarium root rot

Scouting Notes

  • Younger plants are very susceptible and exhibit wilting symptoms in individual leaves.
  • Scout for cucumber beetle infestation and cucumber beetle feeding damage on healthy plants.